Numerous devices are available as object position detectors for use in computer systems and other applications. The most familiar of such devices is the computer mouse. While extremely popular as a position indicating device, a mouse has mechanical pans and requires a surface upon which to roll its position ball. The mouse translates movement of the position ball across the rolling surface as input to a computer. The growing popularity of laptop or notebook computers has created a significant problem for mouse type technologies which require a rolling surface. Laptop computers are inherently portable and designed for use in small confined areas such as, for example, airplanes, where there is insufficient room for a rolling surface. Adding to the problem is that a mouse usually needs to be moved over long distances for reasonable resolution. Finally, a mouse requires the user to lift a hand from the keyboard to make the cursor movement, thereby upsetting the prime purpose, which is usually typing on the computer.
As a result of the proliferation of laptop computers and the standardization of the Windows operating environment, a need for a reliable, portable, and integrated form of mouse control has arisen. To satisfy this need, mechanical ball or shaft rolling technologies, such as, for example, track balls have been designed for use with laptop computers. A track ball is similar to a mouse. A major difference, however is that, unlike a mouse, a track ball does not require a rolling surface. Track balls first appeared as clip-on attachments for laptop computers and then later were integrated within laptop computers.
A track ball is large in size and does not fit well in a volume-sensitive application such as a laptop computer. Furthermore, a track ball is quite cumbersome because it requires practiced dexterity by the user as he or she interacts with the device. Finally, a track ball is not durable and is easily subject to contamination from environmental factors such as dirt, grease, and the like.